Finding the Fourth Proportional to 1,111.06, 1,663.99 and 561.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.06 : 1,663.99 = 561.91 : x
2. Step 2: Convert to fraction form
   1,111.06/1,663.99 = 561.91/x
3. Step 3: Cross multiply
   1,111.06x = 1,663.99 × 561.91
4. Step 4: Simplify right side
   1,111.06x = 935,012.62
5. Step 5: Solve for x
   x = 935,012.62/1,111.06
6. Step 6: Final answer
   x = 841.55